Controllers and software ease motor applications

Edited by the Electronicstalk editorial team Mar 28, 2008

16bit digital signal controllers target motor control designs requiring increased memory, performance or enhanced peripherals.

Microchip has released 10 new 28- and 44-pin 16bit digital signal controllers (DSCs) for motor control designs requiring increased memory, performance or enhanced peripherals, while obtaining cost and size savings by using lower pin-count devices.

Microchip also announces a new motor control development platform based on the popular Explorer 16 development board.

Additionally, Microchip has announced five motor control software packages for: power factor correction (PFC), sensorless field oriented control (FOC) of a PMSM motor, sensorless FOC of an ACIM motor, sensorless control of a BLDC motor using back EMF filtering and sensorless BLDC control with back-EMF filtering using a majority function.

The 10 new devices bring Microchip's total count of motor control DSCs featuring three-phase motor control PWMs up to 36 devices.

The newly announced devices come in packages as small as 6 x 6mm, and offer up to 128Kbyte of Flash memory for large proprietary algorithms such as observer motor control models; integration of motor control algorithms with system-level control; communication stacks such as CAN; and graphic libraries for displays.

Two of the new devices feature 16bit D/A convertors that can be used for motor noise reduction strategies or audio messaging.

A user-selectable 10 or 12bit A/D convertor is also available on chip.

In 10bit mode, the ADC features up to four sample and hold circuits that can be triggered simultaneously - especially useful for synchronised sampling strategies to improve control loop performance.

All of the new motor control DSCs have a flexible three-phase PWM controller, plus two additional PWM outputs on a separate timebase, which are ideal for PFC as that requires a control loop that is over 30x faster than a typical motor control loop.

PFC is increasingly required for mains-powered motors and Microchip has issued a software solution published as application note AN1106 that can be downloaded from Microchip's website.

The new devices also feature two quadrature encoder interfaces for position-sensing applications.

For advanced, cost-sensitive motor control applications, sensorless strategies may be the preferred approach.

Microchip offers four new software solutions addressing these needs.

Sensorless FOC software for controlling PMSM motors is available and described in application note AN1078.

FOC software for controlling ACIM motors is contained in application note AN1162.

This software is advantageous for applications that benefit from high efficiency coupled with excellent torque control, such as air conditioning or refrigeration compressors, or washing machines.

Also available are two new sensorless BLDC software solutions: application note AN1083 "BLDC control using back-EMF filtering" and application note 1160 "Sensorless BLDC control with back-EMF filtering using a majority function".

These application notes are expected to be popular for cost-sensitive BLDC applications, such as automotive fuel pumps and appliances.

For demonstration and development, the new PICtail Plus Motor Control daughtercard (part number AC164128) provides an interface between Microchip's general-purpose Explorer16 Development board (part number DM240001) and Microchip's existing high voltage (part number DM300021) or low voltage (part number DM300022) motor drive power modules.

Used with the MPLAB ICD 2 in-circuit programmer/debugger (DV164005) and Microchip's free MPLAB integrated development environment, these tools comprise a complete motor control development environment supporting the whole dsPIC33 motor control family for both sensor and sensor-less control algorithms.

The new devices are sampling now and are expected to be available in volume during Q2 2008.

The application notes and related software are all available today as free downloads from the Microchip website.

The new PICtail Plus Motor Control daughtercard is available now and includes a dsPIC33FJ256MC710 plug-in module for the Explorer 16.